Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
267 words
A process for preparing a polyamide fiber excellent in strength, comprising the steps of: spinning a polyamide having a relative viscosity of not less than 2.3 in a melt state through a spinning orifice to produce filaments; introducing the filaments to a cooling zone for cooling; sealing the atmosphere between the spinning orifice and the cooling zone with a heated inert gas; taking up the filaments to make an index of birefringence of 13×10 -3 or less; drawing the filaments taken up by: (a) transferring the filaments onto a first supply roller and then a second supply with application of a pre-draft of less than 20% between the first supply roller and the second supply roller; (b) transferring the resultant pre-drafted filaments onto a first draw roller kept at a temperature of not lower than 100° C. while jetting super-heated steam of not lower than 200° C. from a jet nozzle, provided between the second supply roller and the first draw roller, onto the pre-drafted filaments so as to achieve a first drawing of not less than 50% of the total drawing capacity; and (c) transferring the resulting drawn filaments onto a second draw roller kept at a temperature of not lower than 150° C., while passing the drawn filaments through a heating zone provided between the first draw roller and the second draw roller, with the temperature at the entrance to the heating zone being lower than the temperature at the exit from the heating zone, to achieve a second drawing; and relaxing the resultant drawn filaments at a proportion of 3 to 15% by heating.
Claim 2
Dependent Claim
267 words
A process for preparing a polyamide fiber excellent in strength, comprising the steps of: spinning a polyamide having a relative viscosity of not less than 2.3 in a melt state through a spinning orifice to produce filaments; introducing the filaments to a cooling zone for cooling; sealing the atmosphere between the spinning orifice and the cooling zone with a heated inert gas; taking up the filaments to make an index of birefringence of 13×10 -3 or less; drawing the filaments taken up by: (a) transferring the filaments onto a first supply roller and then a second supply with application of a pre-draft of less than 20% between the first supply roller and the second supply roller; (b) transferring the resultant pre-drafted filaments onto a first draw roller kept at a temperature of not lower than 100° C. while jetting super-heated steam of not lower than 200° C. from a jet nozzle, provided between the second supply roller and the first draw roller, onto the pre-drafted filaments so as to achieve a first drawing of not less than 50% of the total drawing capacity; and (c) transferring the resulting drawn filaments onto a second draw roller kept at a temperature of not lower than 150° C., while passing the drawn filaments through a heating zone provided between the first draw roller and the second draw roller, with the temperature at the entrance to the heating zone being lower than the temperature at the exit from the heating zone, to achieve a second drawing; and relaxing the resultant drawn filaments at a proportion of 3 to 15% by heating.
Claim 3
Dependent Claim
28 words
The process as defined in claim 1, further comprising the step of: applying an oiling agent to the filaments after the filaments are cooled in the cooling zone.
Claim 4
Dependent Claim
35 words
The process as defined in claim 1, wherein the first drawing is achieved in two positions, one being at the exit of the second supply roller and the other at the jetting with super-heated steam.
Claim 5
Dependent Claim
48 words
The process as defined in claim 1, further comprising the step of: providing a nip roller heated at a temperature of 10° to 30° C. higher than that of the second supply roller, so as to nip the pre-drafted filaments at the exit of the second supply roller.
Claim 6
Dependent Claim
17 words
The process as defined in claim 1, wherein the heating zone is heated by a non-contact heater.
Claim 7
Dependent Claim
16 words
The process as defined in claim 2, wherein the oiling agent is a non-aqueous oiling agent.
Claim 8
Dependent Claim
22 words
The process as defined in claim 1, wherein the second supply roller is kept at a temperature of less than 100° C.
Claim 9
Dependent Claim
22 words
The process as defined in claim 7, wherein the second supply roller is kept at a temperature of 30° to 80° C.
Claim 10
Dependent Claim
27 words
The process as defined in claim 5 wherein super-heated steam is jetted onto the drawn filaments from a nozzle provided at the exit to the heating zone.